Recently, as energy consumption is increased, a solar cell apparatus has been developed to convert solar energy into electric energy.
In particular, a CIGS-based solar cell apparatus, which is a PN hetero junction apparatus having a substrate structure including a glass substrate, a metallic back electrode layer, a P type CIGS-based light absorbing layer, a high-resistance buffer, and an N type window layer, has been extensively used.
In addition, studies and research have been performed to improve electric characteristics of the solar cell apparatus, such as the low resistance and high transmittance rate. Further, studies and research have been pursued to develop a flexible solar cell apparatus.